1. Static Storage Class
Storage
Default Initial Value
Scope
Life
Memory
0
Local to the block in which
the variable is defined
Variable persists between
different function calls

2. main( )
{
increment( ) ;
increment( ) ;
increment( ) ;
}
increment( )
{
auto int i = 1 ;
register int j = 1 ;
static int k = 1 ;
i++ ;
j++ ; k++ ;
printf ( ”%d %d %d”, i, j, k ) ;
2 2 2
2 2 3
2 2 4
}

3. When to Use Static
main( )
{
f( )
f( ) ;
p =
int a = 20 ;
return ( &a ) ;
}
printf ( ”%d”, *p ) ;
}
int *p ; int * f( ) ;
{
a p
20 250
250
int * f( ) char ** char ** ff (( iinntt **,, ffllooaatt ** )) ;;
static int a = 20 ;

4. External Storage Class
main( )
{
printf ( ”%d”, a ) ;
increment( ) ;
increment( ) ;
decrement( ) ;
printf ( ”%d”, a ) ;
}
increment( )
{
a++ ; printf ( ”%d”, a ) ;
} decrement( )
{
a-- ; printf ( ”%d”, a ) ;
}
10
11
12
11
11
int a = 10 ;
Output

5. Declaration V/s Definition main( )
{
extern int a ;
printf ( ”%d”, a ) ;
increment( ) ;
increment( ) ;
decrement( ) ;
printf ( ”%d”, a ) ;
ncrement( )
{
extern int a ;
float square ( float ) ;
float square ( float )
{
..
..
}
DDeeccllaarraattiioonn
} a++ ; printf ( ”%d”, a ) ;
decrement( )
{
extern int a ;
} a-- ; printf ( ”%d”, a ) ;
}i
int a = 10 ;
DDeeccllaarraattiioonn
DDeeccllaarraattiioonn
DDeeffiinniittiioonn
float square ( float ) ;
float square ( float )
{
..
..
}
DDeeffiinniittiioonn

6. Declaration V/s Definition main( )
{
extern int a ;
printf ( ”%d”, a ) ;
increment( ) ;
increment( ) ;
decrement( ) ;
printf ( ”%d”, a ) ;
extern int a ;
int a = 10 ;
decrement( )
{
extern int a ;
}i
ncrement( )
{
a++ ; printf ( ”%d”, a ) ;
}
a-- ; printf ( ”%d”, a ) ;
}

7. Declaration V/s Definition main( )
{
extern int a ;
printf ( ”%d”, a ) ;
increment( ) ;
increment( ) ;
decrement( ) ;
printf ( ”%d”, a ) ;
int a = 10 ;
increment( )
{
extern int a ;
decrement( )
{
extern int a ;
}
a++ ; printf ( ”%d”, a ) ;
}
a-- ; printf ( ”%d”, a ) ;
}

8. Two Types Of Conflicts
int a = 10 ;
main( )
{
int a = 20 ;
{
int a = 30 ;
printf ( ”%d”, a ) ;
}
printf ( ”%d”, a ) ;
}
printf ( ”%d”, a ) ;
30
20

9. External Storage Class
Storage
Default Initial Value
Scope
Life
Memory
0
Global
Till execution of the
program doesn’t end

10. Which is The Most Powerful
Automatic
Register
Static
External
All other cases
For frequently
used variables
If variable is to live
across function calls
If variable required by
all functions

11. Ctrl F9
F9
F7
F8
C Preprocessor
Compile and Execute
Compile
Step into
Step over

12. main( )
{
int a = 10 ;
float b = 3.5 ;
display( ) ;
printf ( ”Hello” ) ;
} display( )
{
printf ( ”Nagpur” ) ;
}

13. A Closer Look
Hand written program
Text Editor
C Source Code
Preprocessor
Expanded source code
Compiler
Object code
Linker
Executable code
C :
Helps in typing TC
WS4 . .
a program
WORKS
Helps in typing
a program
Expands the
source code
Expands the
source code
Converts expanded source
code into machine language
Converts expanded source
code into machine language

14. Why IDE
Editor
Preprocessor
Compiler
Linker
Ctrl F9
TTuurrbboo CC//CC++++
Preprocesses,
Compiles, Links
and Executes

15. Types of Preprocessor Directives
File Inclusion
Macro Expansion
Conditional Compilation
Miscellaneous Directives

16. Preprocessor In Action
# include ”goto.c”
main( )
{
Compiler
clrscr( ) ;
gotorc ( 10, 20 ) ;
printf ( ”Hello !” ) ;
}
Source Code
Ctrl F9
Preprocessor
main( )
{
clrscr( ) ;
gotorc ( 10, 20 ) ;
printf ( ”Hello !” ) ;
}
gotorc( - , - )
{
-
-
-
}
Expanded source code

17. Unresolved
Externals
gotorc( - , - )
{
-
-
-
} Compiler
main( )
{
-
-
-
}
machine language
code of gotorc( )
machine language
code of main( )
Error Why?

18. Solution
m/c language code
of gotorc( )
m/c language code
of main( )
m/c language code
of clrscr( )
m/c language code
of printf( )
LLiinnkkeerr
Executable code

19. Your wish
# include ”goto.c”
# include goto.c
C :
TC
WS4 . .
WORKS
INCLUDE
INCLUDE DIRECTORIES
LIBRARY DIRECTORIES
C: TC INCLUDE
C: TC LIB
C: TC WORKS
C: TC
OUTPUT DIRECTORY
SOURCE DIRECTORIES

20. CChhaapptteerr 66
CChhaapptteerr 66